FFmpeg ProRes output -- no BT470GB flag

[rgr]

I am converting video to ProRes format with options:

-c:v prores_ks -profile:v 1 -colorspace bt470bg

I see that ffmpeg wants to do this too:

Stream #0:0: Video: prores (LT) (apcs / 0x73637061), yuv422p10le(tv, bt470bg/unknown/unknown, progressive), 720x576 [SAR 16:15 DAR 4:3]

But the output file does not have the appropriate flag:

Video
ID : 1
Format: ProRes
Format version: Version 0
Profile format: 422 LT
Codec ID: apcs
Duration: 15 min 37 sec
Bit rate mode: Variable
Bit rate: 56.7 Mbps
Width: 720 pixels
Height: 576 pixels
Display aspect ratio: 4:3
Frame rate mode: Constant
Frame rate: 50,000 FPS
Color space : YUV
Chroma subsampling: 4:2:2
Scan type: Progressive
Bits/(Pixel*Frame) : 2,732
Stream size: 6.18 GiB (100%)
Writing library: Lavc

So how to do it properly?

[ProWo]

You have to set colormatrix and colortrace too.

[Sharc]

Do you want to convert the colorspace by using the corresponding matrix, or just flag it?
Maybe this helps:
https://medium.com/invideo-io/talking-about-colorspaces-and-ffmpeg-f6d0b037cc2f
https://www.canva.dev/blog/engineering/a-journey-through-colour-space-with-ffmpeg/
https://stackoverflow.com/questions/61834623/how-to-use-ffmpeg-colorspace-options

[rgr]

Thanks.
This is the only combination that worked for me. Missing one causes all flags to be missing.

-colorspace bt470bg -color_primaries bt470bg -color_trc gamma28 -color_range tv

I think this is a bug in ffmpeg.

[rgr]

Do you want to convert the colorspace by using the corresponding matrix, or just flag it?
Maybe this helps:
https://medium.com/invideo-io/talking-about-colorspaces-and-ffmpeg-f6d0b037cc2f
https://www.canva.dev/blog/engineering/a-journey-through-colour-space-with-ffmpeg/
https://stackoverflow.com/questions/61834623/how-to-use-ffmpeg-colorspace-options

Just flag it (source: miniDV)


However, I have a question by the way.
AViSynth script, the source is let's say BT709 YUV420.
I use the command: ConvertTo422() (no parameters)
The output will be BT709/YUV422 or BT601/YUV420. I haven't tested it, but according to the instructions, ConvertToYUVxxx gives BT601 by default.

[hello_hello]

However, I have a question by the way.
AViSynth script, the source is let's say BT709 YUV420.
I use the command: ConvertTo422() (no parameters)
The output will be BT709/YUV422 or BT601/YUV420. I haven't tested it, but according to the instructions, ConvertToYUVxxx gives BT601 by default.

The matrix is only required for conversions between YUV and RGB. As far as I know the convert functions can't change the matrix when converting from one flavor of YUV to another, so if you want to convert a YUV BT709 source to BT601, you need to convert it to RGB with matrix="Rec709", and then back to YUV with matrix="Rec601".

[Sharc]

The matrix is only required for conversions between YUV and RGB. As far as I know the convert functions can't change the matrix when converting from one flavor of YUV to another, so if you want to convert a YUV BT709 source to BT601, you need to convert it to RGB with matrix="Rec709", and then back to YUV with matrix="Rec601".

AFAIK the colormatrix(mode=xxxx) filter can do the conversion staying within YUV in one step:
http://avisynth.nl/index.php/ColorMatrix

[rgr]

However, I have a question by the way.
AViSynth script, the source is let's say BT709 YUV420.
I use the command: ConvertTo422() (no parameters)
The output will be BT709/YUV422 or BT601/YUV420. I haven't tested it, but according to the instructions, ConvertToYUVxxx gives BT601 by default.

The matrix is only required for conversions between YUV and RGB. As far as I know the convert functions can't change the matrix when converting from one flavor of YUV to another, so if you want to convert a YUV BT709 source to BT601, you need to convert it to RGB with matrix="Rec709", and then back to YUV with matrix="Rec601".

Maybe someone will find it useful.
ColorMatrix honors frame properties when converting to RGB.
Of course, when converting from RGB to YUV, you must provide the matrix (by default it converts Rec601) and correctly sets the new frame properties.